Photodegradation of polyethylenes: Comparative effect of Fe and Ca-stearates as pro-oxidant additives

Pablos, Jesús L.; Abrusci, C.; Marı́n, Irma; López‐Marín, Josefa; Catalina, F.; Espí, Enrique; Corrales, Teresa

doi:10.1016/j.polymdegradstab.2010.07.003

Cited by 75 publications

(39 citation statements)

References 27 publications

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“…Furthermore, this decrease is more significant for higher additive loads (sample B). A similar trend was reported for both naturally and artificially photo-degraded polyethylene formulations with pro-oxidant/pro-degradant additives compared to pure polymers [15,17,23,28,34].…”

Section: Changes In Thermal Propertiessupporting

confidence: 81%

“…This decrease of thermal stability observed in these UV-aged samples can probably be explained by the greater amount of low molecular weight fractions and chemical impurities (mainly oxygenated groups) resulting from photo-oxidation, which decompose at relatively lower temperatures, indicating that samples containing pro-oxidant/pro-degradant additive have undergone previous degradation [15,28,34]. Additionally, a concomitant decrease in the residue upon thermal degradation of these photo-oxidized samples is also apparent ( Table 2).…”

Section: Accepted Manuscriptmentioning

confidence: 93%

See 1 more Smart Citation

Thermal characterization of the oxo-degradation of polypropylene containing a pro-oxidant/pro-degradant additive

Contat‐Rodrigo

2013

Polymer Degradation and Stability

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The oxo-degradation process of polypropylene (PP) samples containing different concentrations (4% and 10% w/w) of pro-oxidant/pro-degradant additive Envirocare TM AG1000C was investigated under accelerated test conditions. Samples were initially exposed to UV radiation for 300 hours. The tendency to biodegradation in soil medium of these UV-aged samples was then indirectly assessed by an indirect method for a period of 6 months. The entire degradation process of these materials was first examined by monitoring changes in their morphological properties (melting temperature, maximum lamellar thickness and crystallinity) with the aging time, by Differential Scanning Calorimetry (DSC). Then, changes in the thermal properties (onset temperature and maximum decomposition temperature) of these materials with the aging time were analysed by Thermogravimetric Analysis (TGA). Furthermore, the kinetics of the thermal decomposition of these PP samples with pro-oxidant/prodegradant was also studied during the oxo-degradation process, by means of the Chang differential method. During exposure to UV radiation, the more significant changes in the morphological and thermal properties that were detected in PP samples containing M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPTpro-oxidant/pro-degradant additive compared to pure PP, clearly suggest a higher level of oxidation in these samples, confirming the effectiveness of this pro-oxidant/prodegradant additive in promoting the abiotic oxidation of polypropylene during UVirradiation. Moreover, the level of oxidation observed in UV-aged samples seems to be dependent on the additive load.On the other hand, during incubation in soil medium, changes in the morphological and thermal properties of previously photo-oxidized PP samples with pro-oxidant/prodegradant were detected that indirectly support a certain progress of oxidation, indicating that previous abiotic oxidation can promote further degradation of the polypropylene matrix by soil microorganisms. In general, both morphological and thermal properties exhibit a non-linear dependency with the incubation time in soil, supporting the idea that biodegradation is a complex process that occurs in different stages. Furthermore, the extent of the changes in these properties during soil incubation was found to be proportional to the pro-oxidant/pro-degradant load and the previous photo-oxidation level.

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Section: Changes In Thermal Propertiessupporting

confidence: 81%

Section: Accepted Manuscriptmentioning

confidence: 93%

Thermal characterization of the oxo-degradation of polypropylene containing a pro-oxidant/pro-degradant additive

Contat‐Rodrigo

2013

Polymer Degradation and Stability

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“…Assim como para o PEBD e PELBD , os resultados mostram que os agentes pró-degradantes fundamentados nos metais de transição Fe e Mn promovem a degradação termooxidativa do PEAD. Entretanto, a intensidade de aceleração do processo de termooxidação do Mn é significativamente superior ao Fe, conforme apresentam os resultados; este comportamento é verificado em trabalhos anteriores [26,31,37] . Esta diferença ocorre para todas as formulações com concentração similar de metal de transição, como, por exemplo, entre as formulações FeII-195 (195 ± 11 mg/kg) e MnII-191 (191 ± 11 mg/kg), onde o tempo de indução, detectado pelo equipamento, para formação de carbonila na formulação FeII-195 é de, aproximadamente, 2.620 horas, enquanto que para a formulação MnII-191 o tempo de indução é inferior a 281 horas (mais de nove vezes menor); o tempo de indução para a formulação PEAD (formulação controle -sem adição de pró-degradante) é de, aproximadamente, 3.235 horas.…”

Section: Resultsunclassified

“…Entretanto, estudos mostraram que o Co foi superior ao Fe em fotooxidação do PEBD e o Fe apresentou desempenho superior ao Cu neste mesmo estudo [37] . Estearato de Fe e estearato de Ca foram comparados, como pró-degradantes, em fotooxidação do PEBD e o Fe apresentou melhor desempenho, seja na fotooxidação natural ou acelerada [31] . Quanto aos tipos de polietilenos, a degradação abiótica oxidativa segue a seguinte ordem decrescente de intensidade: PEBD > PELBD > PEAD; a maior resistência aos processos oxidativos de degradação do PEAD é função da menor quantidade de carbono terciário nas moléculas e maior percentual de cristalinidade [30] .…”

Section: Introductionunclassified

Avaliação de sistemas pró-degradantes na degradação termooxidativa do PEAD

2015

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ResumoSistemas pró-degradantes fundamentados em estearatos de ferro e de manganês e o aditivo comercial d2w, fundamentado em sal orgânico de manganês, foram avaliados em filmes de polietileno de alta densidade (PEAD) em ambiente termooxidativo (estufa a 80 °C e ausência de luz). A degradação termooxidativa foi monitorada por propriedades mecânicas, espectroscopia de infravermelho e cromatografia por exclusão de tamanho. Os resultados mostram que ambos os metais aceleram a degradação termooxidativa do PEAD. Entretanto, o desempenho pró-degradante do estearato de manganês é significativamente superior ao do estearato de ferro. Para o ferro, a degradação aumenta com o aumento da concentração do metal, enquanto que o manganês apresenta valor máximo de degradação em função da concentração. O estado de oxidação do ferro não interfere no desempenho pró-degradante. O aditivo comercial d2w TM acelera, significativamente, a termooxidação do PEAD, mas seu desempenho é inferior ao estearato de manganês provavelmente em função do conjunto de estabilizantes adicionados ao produto comercial. Palavras-chave: degradação, PEAD, estearato de ferro, estearato de manganês, pró-degradante. AbstractThe evaluation of pro-degradant systems based on iron and manganese in the form of metallic stearate, and d2w TM commercial additive, based on organic salt of manganese, was carried out on films of high density polyethylene (HDPE) in thermal oxidative conditions (80 °C oven and absence of light). The thermo oxidative degradation was monitored by mechanical properties, by infrared spectroscopy and by size exclusion cromatography. The results show that both metals accelerate thermal oxidative degradation of HDPE. However, the pro-degrading performance of manganese is significantly higher than iron. Considering iron, the degradation increases with increasing concentration of the metal, while manganese presents the maximum value of degradation depending on the concentration. The oxidation state of iron does not interfere with pro-degrading performance. The commercial additive d2w TM significantly accelerates HDPE thermo-oxidation, but its performance is lower than manganese stearate as a function of the set of stabilizing additives to be added to the commercial product.

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“…Nowadays, several authors have already studied the influence of (POA) on the photooxidation of polymers; for instance, Pablos and coworkers [8] studied the effect of iron and calcium stearates on the photodegradation of polyethylene (LDPE and LLDPE) under natural and artificial exposure using chemiluminescence. Changes in chemical structure were monitored through Fourier transform infrared spectroscopy (FTIR) and gas chromatography-mass spectrometry (GC-MS) was used to follow changes in molecular weight and the content of degradation products.…”

Section: Introductionmentioning

confidence: 99%

A Comparative Study of the Photodegradation of Two Series of Cyclic Olefin Copolymers

Gutiérrez-Villarreal¹,

Zavala-Betancourt²

2017

International Journal of Polymer Science

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A series of commercial cyclic olefin copolymers (COC), namely, ethylene-norbornene (E-NB) and ethylene-tetracyclododecene (E-TD), were processed as thin films with thicknesses of 25 m by an extrusion process. The photodegradation of neat and formulated films with different metal stearates (Fe, Co, and Mn) was investigated using an ultraviolet (UV) light lamp (340 nm) for a period of 30 days in an accelerated weathering tester model QUV from Q-LAB according to the ASTM D 5208-01 standard practice. Changes in carbonyl index (CI) and tensile properties were used to evaluate the photodegradation of the films and other properties, such as variation by DSC, were also analyzed. The present study reveals that (E-NB) copolymers show higher sensitivity to photodegradation than (E-TD) resins, in the absence and presence of metal stearates. We also find that the Fe salt shows the highest oxidative activity.

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Photodegradation of polyethylenes: Comparative effect of Fe and Ca-stearates as pro-oxidant additives

Cited by 75 publications

References 27 publications

Thermal characterization of the oxo-degradation of polypropylene containing a pro-oxidant/pro-degradant additive

Thermal characterization of the oxo-degradation of polypropylene containing a pro-oxidant/pro-degradant additive

Avaliação de sistemas pró-degradantes na degradação termooxidativa do PEAD

A Comparative Study of the Photodegradation of Two Series of Cyclic Olefin Copolymers

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